1. Field of the Invention
The present invention relates to liquid crystal display manufacturing technology, especially to a connection pad group which is used for photo-alignment process of liquid crystal panel and is easy to apply voltage thereto.
2. Description of the Related Art
In the manufacturing process of liquid crystal display device, in order to stably control the pre-tilt angle of liquid crystal molecules, manufacturers have developed a photo-alignment technology.
With reference to FIG. 1, a conventional thin-film transistor liquid crystal panel includes a color filter substrate 90, a thin-film transistor array substrate 91 opposite to the color filter substrate 90, alignment films 92 disposed on the inner surfaces of the color filter substrate 90 and the thin-film transistor array substrate 91, and a liquid crystal layer 93 disposed between the color filter substrate 90 and the thin-film transistor array substrate 91. The liquid crystal layer 93 has liquid crystal molecules 930 and further has monomers 931 which are used for photo-alignment.
When performing the photo-alignment process, a voltage-applying device is electrically connected to the electrodes of the color filter substrate 90 and the thin-film transistor array substrate 91 so as to provide an electric potential difference therebetween to make the liquid crystal molecules 930 to tilt under an electric field; meanwhile, a light source device emits ultra-violet lights 800 into the liquid crystal layer 93 so as to make the monomers 931 to form a polymer layer 9310. The polymer layer 9310 can accurately keep the liquid crystal molecules 930 to have the same pre-tilt angle.
In general, with reference to FIG. 2, when manufacturing foregoing liquid crystal panel, the manufacturer first disposes a plurality of thin-film transistor array blocks 910 on a large-sized glass substrate 9, then correspondingly disposes a liquid crystal layer and a color-filter substrate 90 on each of the thin-film transistor array blocks 910 to form a plurality of panel units, and then the glass substrate is cut into a plurality of individual liquid crystal panels.
The aforementioned photo-alignment process is performed before the cutting process. During applying voltages, a connection pad row 7 is mounted at one side of the glass substrate 9, wherein according to the number of the panel units on the glass substrate 9, the connection pad row 7 has a plurality of connection pads arranged side by side for electrical connection of the voltage-applying device.
In the voltage-applying step of the traditional photo-alignment process, each panel unit requires at least six connection pads for the voltage-applying device to perform electrical connection and apply voltages for performing the photo-alignment process. For example, when the glass substrate 9 includes three panel units, with further reference to FIG. 3, the connection pad row 7 has nineteen connection pads, respectively labeled 1-19, wherein, connection pads 1-6 are in a first connection pad group 70a, connection pads 7-12 are in a second connection pad group 70b, connection pads 13-18 are in a third connection pad group 70c. The connection pads in each of the connection pad group are respectively connected to the related conductive lines of the corresponding panel unit. The conductive lines are arranged in a pixel array and include common lines, gate lines activating odd-numbered pixel rows, gate lines activating even-numbered pixel rows, data lines transferring data of red-pixels, data lines transferring data of green pixels and data line transferring data of blue-pixels. And the nineteenth connection pad is correspondingly connected to the common electrodes on the color filter substrates of the three panel units.
However, because of those excessive connection pads, the voltage-applying device has to use a lot of probes for electric connection; meanwhile, since the size of each connection pad is only 3 mm×5 mm and may affect the contact accuracy of the probes of the voltage-applying device, if there is a positional deviation in the arrangement of the probes or the positions of the connection pads, or the probes have been worn down, poor electrical contact between the voltage-applying device and the connection pad row 7 may occur and cause the photo-alignment process to fail.
Therefore, it is necessary to provide a connection pad group for photo-alignment process of liquid crystal panel to overcome the problems existing in the conventional technology.